Error “Microsoft.Exchange.Monitoring.ProtocolException: Authentication failed. The connection is being closed. The handshake failed due to an unexpected packet format. Server response while making connection:[]. —> System.IO.IOException: The handshake failed due to an unexpected packet format.” was due to the missing intermediate certification authority (CA) certificate. I unified the cert (export/import) among CAS servers to get it fixed.

Microsoft Exchange error “Exception has been thrown by the target of an invocation” indicates issues for background process to modify the settings of existing mailbox object.In my case, I could not enable an email address policy for a user mailbox. It was caused by wrong declaration of %rxy and replacing subsequent characters in the policy (missing r character).

I have recently came to a need to migrate many receive connectors from Exchange 2010 to Exchange 2013. I helped myself by creating a function, which migrates all connectors from one server to another. Connectors with same settings (bindings, Remote IP ranges and port) are skipped. Function doesn’t automatically grant anonymous relay permission, because I think it is worth setting manually after check of migrated connectors, since almost all environments are messy :).

Don’t forget, that there is major architecture change in Exchange 2013! All external e-mails should flow via FrontEndTransport service! The detailed description with consequences is mentioned here:

MS support requested to modify the time limit of a cross-forest AutoDiscover operation via the RecipientResolutionTimeoutInSeconds property (KB928812). Just adding the following line into Web.config was needed:

The line added and the availability service destroyed (affected OoO, free/busy, Autodiscover).

It was caused by an invalid form of double quotation marks (despite copy/paste through notepad).